This sounds like a good experiment, and you already have a great answer, vinegar added to the baking soda will bubble fiercely.
I've included a couple of links to experiments that you may like, also, your question alone makes a good experiment. You could place baking soda in 4 or 5 different clear plastic cups and pour different liquids over top and record the reactions. Vinegar causes the baking soda to bubble due to the acid, so you may want to try milk in another cup, and then lemon juice also an acid in the next, try tap water and then orange juice which is another acid. Record your results and see if one acid caused more of a boiling action than the others. Good luck and have fun with this!